The proposed project aimed at examining two major aspects of the regulatory biochemical functions of glucocorticoids in specific catecholaminergic and serotonergic neurons in the brain. One aspect is concerned with the role of these hormones in biochemical regulation of neurotransmission, particularly the two rate-limiting neurotransmitter-synthesizing enzymes, tyrosine hydroxylase and tryptophan hydroxylase. The other aspect is concerned with the biochemical characterization of cytosol glucocorticoid receptor protein(s) in specific types of neurons, and the regulatory effect of glucocorticoids on the adenylate cyclase system. Work in progress in the current year has localized cytosol glucocorticoid receptors in various discreet brain nuclei and the superior cervical ganglion. The ganglion has emerged as an excellent system whereby neural regulation of receptor binding capacity and the steroid action on cholineric terminals (leading to induction of tyrosine hydroxylase) can be examined. In addition, specific glucocorticoid binding sites have been identified and characterized on brain synaptic plasma membranes. The relationship between steroid binding and the membrane-bound adenylate cyclase activity is currently under investigation.